Off-Gimbal Optical Position Sensing for Gimbal Systems
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Solution Overview
Problem
Conventional optical systems using on-gimbal position encoders and angle resolvers are bulky, expensive, and require costly data slip rings for signal transfer, introducing non-linearity errors and occupying valuable space, while also being noisy due to high data rates.
Innovation Solution
An optical position sensing system that measures gimbal position off-gimbal using a light source and detector, where a position sensing light beam is transmitted along an optical coude path, altered by an optical element on the gimbal, and detected off-gimbal, eliminating the need for data slip rings and allowing space for larger optics or sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If on-gimbal position encoders or angle resolvers are used, then gimbal position measurement is achieved, but the system becomes bulky, expensive, and requires data slip rings that introduce non-linearity errors and noise
Solution Approach 1:
The patent replaces mechanical position encoders and angle resolvers with an optical measurement system. A light source projects a beam through a coude path to an optical element on the gimbal, and a detector measures the reflected light intensity to determine position. This substitution eliminates mechanical complexity, bulky components, and the need for data slip rings while maintaining measurement capability.
Solution Approach 2:
The patent introduces an intermediary optical system (light source, coude path, optical element, detector) to transfer position information from the rotating gimbal to stationary components without direct electrical connections. The optical element modulates light intensity based on gimbal position, and this optical signal is detected off-gimbal, eliminating the need for electrical data slip rings.
2Measurement precision
If on-gimbal position encoders or angle resolvers are used, then gimbal position measurement is achieved, but valuable space on the gimbal platform is consumed
Solution Approach 1:
The patent extracts the position measurement function from the gimbal platform itself. Instead of mounting encoders or resolvers on the gimbal, the system uses a light source and detector positioned off-gimbal. The optical element on the gimbal only needs to modulate light, requiring minimal space, while the bulky measurement components are relocated to the stationary structure.
3Loss of information
If data slip rings are used to transfer signals from on-gimbal position encoders or angle resolvers, then data transfer is achieved, but the slip rings become expensive and noisy due to high data rate requirements
Solution Approach 1:
The patent replaces electrical data slip rings with an optical signal transmission system. Position information is encoded in the intensity of reflected light rather than electrical signals. Since the light intensity modulation occurs at the gimbal and is detected off-gimbal, no high-speed electrical data transfer across the rotating interface is needed, eliminating noise and cost associated with data slip rings.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces the cost of slip rings, eliminates non-linearity errors, and optimizes space by using optical signals to transfer gimbal position information, enhancing system performance and functionality.
Implementation Method 1
an optical element mounted on an axis of the gimbal and configured to cause a change in an intensity of the position sensing light beam based on rotation of the gimbal about the axis
Implementation Method 2
a light source configured to generate a position sensing light beam, the light source being mounted off-gimbal in the optical system and further configured to transmit the position sensing light beam along an optical coude path of the optical system
Implementation Method 3
a detector mounted off-gimbal in the optical system and configured to receive the position sensing light beam returned from the optical element and to detect the change in the intensity of the position sensing light beam
Data Source
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AI summary
An optical position sensing system and method for sensing a gimbal position in a gimbal-based optical system. One example of an optical position sensing system includes an off-gimbal light source that generates a position sensing light beam and transmits the position sensing light beam along an optical coude path of the optical system, and an on-gimbal optical element that causes a change in an intensity of the position sensing light beam based on rotation of the gimbal about the axis. The system further includes an off-gimbal detector configured to receive the position sensing light beam returned from the optical element and to detect the change in the intensity of the position sensing light beam, and a controller coupled to the detector and configured to determine the gimbal position based on a correlation between the change in the intensity of the position sensing light beam and the gimbal position.